19780011931 has 4 divisors (see below), whose sum is σ = 20418076864. Its totient is φ = 19141947000.

The previous prime is 19780011893. The next prime is 19780011941. The reversal of 19780011931 is 13911008791.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19780011931 - 2²⁹ = 19243141019 is a prime.

It is a super-2 number, since 2×19780011931² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19780011941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 319032420 + ... + 319032481.

It is an arithmetic number, because the mean of its divisors is an integer number (5104519216).

Almost surely, 2^19780011931 is an apocalyptic number.

19780011931 is a deficient number, since it is larger than the sum of its proper divisors (638064933).

19780011931 is an equidigital number, since it uses as much as digits as its factorization.

19780011931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638064932.

The product of its (nonzero) digits is 13608, while the sum is 40.

The spelling of 19780011931 in words is "nineteen billion, seven hundred eighty million, eleven thousand, nine hundred thirty-one".